Multiply.
Explanation: ${1}$ ${9}$ ${3}$ ${2}$ ${2}$ ${1}$ ${\times\vphantom{0}}$ ${2}\times {1}= {2}$ ${2}$ ${30}\times {1}= {30}$ ${3}$ ${900}\times {1}= {900}$ ${9}$ ${1{,}000}\times {1}= {1{,}000}$ ${1}$ ${2}\times {20}= {40}$ ${4}$ ${0}$ ${30}\times {20}= {600}$ ${6}$ ${900}\times {20}= {18{,}000}$ ${8}$ ${1{,}000}\times {20}+10{,}000}= {30{,}000}$ ${3}$ ${+\vphantom{0}}$ ${4}$ ${0}$ ${5}$ ${7}$ ${2}$ $ 40{,}572=1{,}932 \times 21$